The use of multicast protocols and the administration of networks implementing multicast protocols are expanding to support new technologies such as Internet Protocol Television (IPTV) and on demand video. These networks utilize set top boxes (STBs), also referred to as hosts, which request data from a list of sources that are specified by the STBs. The sources are data sources that are available over a multicast network such as IPTV channels. These sources can be streamed using multicast to any number of hosts.
The STBs send their list of sources that they are requesting to receive through the multicast network via a host management protocol (HMP). HMPs include Internet Group Management Protocol (IGMP) and Multicast Listener Discover (MLD). These protocols then communicate the requested list of sources to a multicast routing protocol (MRP) to establish the routing of each requested source to the respective hosts. The MRPs include Protocol Independent Multicast (PIM). In some instances, the requested source interest list is transmitted through an L2 snooping device to a multicast router that executes the MRP.
The HMP communicates the entire list of requested sources to the MRP each time a source interest list is received from a host. This causes the MRP to reprocess sources that it has previously received from the HMP. There are two lists of sources that can be provided by the HMP to the MRP. One list of sources is a set of sources to be included (i.e., the host is requesting that these sources be sent to it) and the other list of source is a set of source to be excluded (i.e., the host is requesting that these resources not be sent to it). Multiple hosts on each subnet send these source interest lists and the HMP constructs and aggregates a source state per subnet comprising the interested sources for all the hosts on that subnet. When any of these hosts sends a new source interest list, the entire aggregated state in the HMP is sent to the MRP.
In a network where a L2 snooping network element is present between the hosts and the multicast router, the HMP on the L2 network element processes the received source interest lists from the hosts to update the snooping state maintained by it and forwards the sources lists in their entirety to the router so that the MRP can update the routing. On the router, the MRP is assisted by a local HMP to process the received source interest lists and communicate state to the MRP. The local HMP must retrieve source identification information from a set of group records in the received HMP messaged requiring significant processing of the received message by the HMP to enable the source identification information within the message to be provided to the MRP.